st->sw = st->xgwa.width / st->subdivision;
st->sh = st->xgwa.height / st->subdivision;
- st->gw = st->xgwa.width / st->sw;
- st->gh = st->xgwa.height / st->sh;
+ st->gw = st->sw ? st->xgwa.width / st->sw : 0;
+ st->gh = st->sh ? st->xgwa.height / st->sh : 0;
st->nsquares = st->gw * st->gh;
gcv.foreground = fg.pixel;